News & Events

Checking air pollution with a smartphone

In a study of air pollution, a small pollution sensor was used to measure black carbon level continuously, combined with an Android smartphone with CalFit software for recording GPS information on user location. Credit: Mark J. Nieuwenhuijsen et al./Environmental Science & Technology

Over the last decade there have been growing concerns on the quality of the air we breath and several pollution detectors have been deployed. The problem is that these are few and cover only a limited zone. What has been noticed is that air quality can change in a very short time, as result of a traffic jam, as an example.

This is what has prompted researchers in Spain, the Netherlands and US to try a different approach: use sensors connected to cell phones to detect pollution levels.

The first experiment was run in Barcelona, Spain, giving to some 50 schoolchildren a smartphone with a connected air sensor. The experiment has shown that although these children spent only 4% of their time traveling to and from school they actually got exposed to air pollution contributing for 13% to the total carbon exposure. This showed that the concentration of pollution in their way to and from school was to such a level that actually had a stronger impact on them.

The experimentation, project BREATHE, was aimed at studying the impact that air pollution can have on brain development (hence the need to involve children in the study). The first step, of course, was to measure the level of black carbon inhaled, as a marker of air pollution. The problem, of course, is in the detection of pollutant using a portable sensor. Trying to detect a broader set of pollutants would have called for more complex sensing devices which would not have fit well with portability. Black carbon, based on studies, was considered as a good indicator of a broader class of pollutants.

The smart phones provided both the connectivity to send the data from the sensor to the data collection center and the exact location the data were referring to using the embedded GPS.

The dynamic and spreading of the data collection provided for a good statistical analyses that complements the information provided by fixed air quality detection systems.